When Raytraced switches to Rendered mode an error in the rendering core happened.
It would be good to save your current work before attempting to use Raytraced again.
Check the following items to see if they help
If the above does not help please contact support tech@mcneel.com. In the subject mention Raytraced failure, and send along the results of the Rhino command _SystemInfo.
If a render was already in progress but stopped before reaching completion you should be able to save the result that was created by then.
Try the checks as outlined in the previous section, and if those steps do not help please contact support at tech@mcneel.com and mention in the subject Rhino Render failure. Send along the results of the Rhino command _SystemInfo.
Please check the same items as in the previous section to see if any of that fixes